I hope I'm not in trouble... I have noticed, over time, that I lose coolant. I could never really put a finger on the cause. The engine doesn't run hot, about 180-210 degrees. It never leaked. Just, every once in a while I had to add coolant or 50/50. Now that I have a lot more light in the garage, I noticed moisture around the intake, and even saw a drop of coolant drip on to the exhaust, and of course, evaporate on contact. It seams obvious that the gasket needs replacing. And hopefully nothing else. Could this mean I have a more serious issue? I say that with my fingers crossed... And if replacing the gasket is the only thing to do, how complicated of a job is it? I'm not that confident about doing the job. I am some what mechanically inclined. I've done tune ups, brake jobs, replaced complete wire harnesses, some fab work, body work, engine and trans swaps, air suspension upgrades, carb rebuilds and other things over the years, but never, for example, done a valve job with any success. My Old Man bailed me out of those situations but, he's gone now. I've never built an engine or trans. I don't want to bite more than I could chew. I would hate to ruin the whole engine because I did something wrong. Is it an easy job? Thanks in advance, fellas. Art.
What model & year Poly?.........have you checked for loose bolts?........where on the intake is the moisture?...........andyd
Changing the intake gasket is not that difficult of a job. And it is common on many engines, for the water passage area of the intake manifold gasket to leak after a while. I like to read the shop manual first, when doing a "new" repair on a car, so I know what I'm in for.
Replacing intake manifold gaskets isn't too bad of a job. The worst that can happen is that it still leaks and you'll be a pro if you have to change it a second time. Once you've got the intake off, this would be a good time to hot-tank the intake to make sure that the cross-over passage is clean.
If its a 1957-66 Plymouth 277-318 Poly with the intake that covers the whole valley the stock style intake gasket set consists of stamped steel side gaskets and foam front and rear gaskets.......the foam gaskets are a PITA and due to their construction and the weight of the intake get squashed out of shape and away from the area they are meant to seal, they are a waste of time.......I don't bother to use the foam gaskets, just throw them straight in the garbage and use a nice bead of silicon about 3/8" wide and same height and have never had a leak at the front/rear of the intake, only issue is when replacing the intake you need to slip a thin blade in to cut the silicon but its not that difficult at the front then just lift the intake to break the manifold free at the rear..........if its an early Poly with the separate intake & valley I can't help as these were never sold here in Oz & I've never played with one but would think from pics I've seen that they would be an easy replace job...........dunno if this helps...........andyd
Thank you for responding. Yes, it is out of a '57 Fury, and the numbers line up with a 318 "A". It is the one with the foam gasket in front and rear, and the intake does take up the whole valley. Now that I'm looking closer, it is mostly in the rear and the bolts are tight. It's in my '54 Royal, so the manual I have doesn't apply to my engine. Anyone happen to have torque specs for the intake?
Yep...........30 Foot Pounds.......btw the heads fit either side so consequently the front water outlet in each cylinder head uses the intake manifold to connect to the water inlet/thermostsat housing which is fine....but as each head has a water outlet then at the rear which is not used as a crossover its sealed off by a cast area on the intake however the intake side gasket has a hole to allow IT to be used either side and sometimes this rear area might leak, although i've not had it leak in that rear area myself............also unless the metal side stamped gasket is rusted away which can happen as its at the water passages, I have on at least one occaison reused the metal gasket by using a thin wipe of silicon.....not the best thing to do but it did work and allowed me a bit of time to chase down a new gasket set..............main thing for me is don't bother with the foam end gaskets, just throw them away..........and Oz Chrysler did exactly what you have done in their 1957-1962 Chrysler Royals which were based on the 1954 Plymouth........they stuck the 318 Poly in them, well 313 to be correct but same engine tho'........ and what I got my 318 Poly from 44yrs ago............regards, andyd.
And yep, its an easy job........tho' if its a stock cast iron intake it is VERY HEAVY.....eat a good breakfast, think nice thoughts and have at it........lol..........but see whether a GENTLE retightening of the intake bolts helps......btw got a pic of the engine bay, I'd be interested in seeing it.........if its ex 57 Fury it should be a twin 4 manifold....yummo!!..........lol......I've got one of those intakes waiting on me to get keen again, tho' the car has a Weiand 4 barrel alloy intake at present ..............andyd
Andyd, thank you for the info. By the way you talk about the cast iron intake, you're really encouraging me to use my cherry picker, just so I don't blow a gasket, or a hemorrhoid....I've been told performance parts for those engines are hard to come by. An aluminum intake would be nice. I ordered some headers online for "early 318 Poly", the exhaust ports didn't line up at all. Just one of those things... Thanks again.
Originally the Plymouth 277-318 Poly came from the factory with the 2 barrel, 4 barrel & twin 4 intakes, all in cast iron, all weigh a lot......lol........the 2x4 factory intake was only available on the 57/58 Furys plus in 58 there was the first of the B blocks at 350 Cubes also with a twin 4 intake available which confuses the issue sometimes,..the 2 barrel intake right thru till the end in 1966 or 67........aftermarket alloy intakes were available as single 4, twin 4 and 3 x 2's by Weiand, Offenhauser and Edelbrock, the Weiand single 4 # 7503 is what I have on my 1940 Dodge Poly, and it was probably the last readily available alloy intake tho' hasn't been common for probably 20 yrs now..I've had mine since the mid 70's.........however there has been a new single 4 alloy intake produced by guys in Texas PolySuperPac.com ...........they are part of the Chrysler Power Magazine from what i understand and have the intakes, headers, cams, alloy valve covers(mine are original Edelbrock that are no longer available), all sorts of engine bits including stroker kits............get a copy of Chrysler Power magazine its had lots of Plymouth Poly articles over the past yr or two.........trust this helps..........btw an easy way to tell if something is for the early 1955/56 Poly or the 1957-66 is just to ask what sort of intake manifold the engine has.........open valley with a separate valley cover is the early version, no separate valley cover is the 57-66 engine....notice I didn't refer to the 57-66 as the "late' engine as the 1964 on 273/318/340/360 is the "Late" or LA series engine and is a wedge headed engine and no intake/head bits fit..............lol.............fun ain't it.............andyd
Andy I don't think Offy ever made any parts for the Poly 318, Weiand and Edelbrock were the only ones. Also IIRC the cast iron manifold weighs 48 lbs and the alloy ones are 18 lbs. If the OP is fitting the manifold he'll need a mate to help or have to use his cherry picker. Not at home at present to check those weights but I know that any of them are heavy, even the ally one.
...hell, those intakes are feather-weight compared to a Ford FE piece... Andy, since you mentioned thew CPM project, I will simply add a note to those who may not have heard: Roland Osborne, owner/publisher of CPM and the bankroll behind the Poly intake project passed away last April. I have no information regarding the future of the 'store' or the magazine. Bruce Toth, Toth Performance, may have some details. Regards. .
stock iron BBC intake is 50 lbs, never been a problem for me to lift them on/off...and I'm a skinny kid.
Yeh, I read in Chrysler Power mag about Rolands Osbornes passing, very sad, we can only hope that his friends and family carry on the inspired work he was doing with regard to the various projects, especially the Poly stuff.......the magazine had only been available here in Oz for the past couple of years........... ........Swifty, I think Offy made a twin 4 intake at least as I thought I'd seen it listed in one of the catalogs in the Rodders Journal Boxed Set ....will have to check.................andyd
Just checked the R/J catalogs and it seems I had a brain fart, only Edelbrock and Weiand listed in the 1962 Moon catalog, prices aren't bad either...........lol................andyd
I always like to make 2 long studs one for the front and one for the back for one head fit the intake over them and let the intake slide down the studs. Keeps the manifold from moving forward or back and knocking off the end gaskets.
Sunbeam, thats a neat idea to use the studs to centre the intake but I still think mopars idea of porous foam as a way to stop oil is not the best thing I've every come across, I'll keep using silicon.............lol.......andyd
The Jalopy Journal
